The crimson barberry (berberis thunbergii autropurpurea) is commonly known as the crimson pygmy barberry. This deciduous, broadleaf shrub is a common element used frequently in landscape design. It is known for its red leaves, compact growth, and low maintenance. It is normally used as a specimen plant or as a border. One drawback is that it has sharp thorns. Therefore, it is suggested that you refrain from planting it near a walkway, where small children play, or where pets may encounter it.
Prune any damaged or diseased branch immediately. You will make a clean cut at the point of the break or where it connects to the main stem. Where you make your cut is depends upon how it will affect the appearance of the plant. However, diseased branches should be removed completely. This can be done at any time of the year. Very often, small shrubs are damaged during the winter season due to snow and ice. These damaged branches can be pruned away at the first signs of spring.
Visually inspect your barberry and snip away any branches that may be interfering with the other plants in your garden bed. You can also snip branches to maintain the rounded shape of the crimson pygmy barberry.
You will use two pruning methods together: They are "heading" and "thinning." Heading cuts are cuts that are made just above a side branch, and thinning cuts are cuts that are made just above a bud. When making a cut above a bud make it about ¼ inch in front of the bud. Pruning to maintain size and shape can be done at any time without harming the plant in any way.
Prune out old, woody canes located in the center of the plant in late winter when the plant is dormant. Removal of old wood encourages/renews the plant. It will produce new growth in the spring, and you will have a much denser plant. Wear gloves to avoid getting pricked by the sharp thorns of the crimson barberry.